Source : Webster's Revised Unabridged Dictionary (1913)

Insolent \In"so*lent\, a. [F. insolent, L. insolens, -entis,
   pref. in- not + solens accustomed, p. pr. of solere to be
   accustomed.]
   1. Deviating from that which is customary; novel; strange;
      unusual. [Obs.]

            If one chance to derive any word from the Latin
            which is insolent to their ears . . . they forth
            with make a jest at it.               --Pettie.

            If any should accuse me of being new or insolent.
                                                  --Milton.

   2. Haughty and contemptuous or brutal in behavior or
      language; overbearing; domineering; grossly rude or
      disrespectful; saucy; as, an insolent master; an insolent
      servant. ``A paltry, insolent fellow.'' --Shak.

            Insolent is he that despiseth in his judgment all
            other folks as in regard of his value, of his
            cunning, of his speaking, and of his bearing.
                                                  --Chaucer.

            Can you not see? or will ye not observe . . . How
            insolent of late he is become, How proud, how
            peremptory?                           --Shak.

   3. Proceeding from or characterized by insolence; insulting;
      as, insolent words or behavior.

            Their insolent triumph excited . . . indignation.
                                                  --Macaulay.

   Syn: Overbearing; insulting; abusive; offensive; saucy;
        impudent; audacious; pert; impertinent; rude;
        reproachful; opprobrious.

   Usage: {Insolent}, {Insulting}. Insolent, in its primitive
          sense, simply denoted unusual; and to act insolently
          was to act in violation of the established rules of
          social intercourse. He who did this was insolent; and
          thus the word became one of the most offensive in our
          language, indicating gross disregard for the feelings
          of others. Insulting denotes a personal attack, either
          in words or actions, indicative either of scorn or
          triumph. Compare {Impertinent}, {Affront},
          {Impudence}.

Source : WordNet®

insolent
     adj 1: marked by casual disrespect; "a flip answer to serious
            question"; "the student was kept in for impudent
            behavior" [syn: {impudent}, {snotty-nosed}, {flip}]
     2: unrestrained by convention or propriety; "an audacious trick
        to pull"; "a barefaced hypocrite"; "the most bodacious
        display of tourism this side of Anaheim"- Los Angeles
        Times; "bold-faced lies"; "brazen arrogance"; "the modern
        world with its quick material successes and insolent
        belief in the boundless possibilities of progress"-
        Bertrand Russell [syn: {audacious}, {barefaced}, {bodacious},
         {bold-faced}, {brassy}, {brazen}, {brazen-faced}]